US Pacific Northwest National Laboratory PNNL recently developed zinc iodine compound battery fluid. Compared to the grid for new energy storage and next-generation conventional flow batteries, its energy density is twice as much.
In laboratory tests the certificate, zinc iodide electrolyte battery discharge capacity of 167 watts per liter, compared to the amount of discharge fluid is zinc-bromine battery was 70 watts, the discharge amount of vanadium flow battery is 15-25 Wh . Developers calculate their new battery can theoretically achieve a higher discharge capacity reaches 322 Wh / liter of electrolyte, but the premise is dissolved electrolyte to continue to increase the quality of the job.
And other fluids batteries, zinc-iodine batteries by the respective anode and cathode electrolyte storage container and intermediate electrolyte mixing containers. When the battery is dead, the electrolyte composition of the two liquid container is the same, both with zinc ions and Zn2 I- iodine ions. When the battery is fully charged, in which a liquid container to add a I3- more iodine ions. When the battery is discharged two electrolyte is pumped into the middle of the reaction vessel. In each cell, the zinc ions across the selective permeability of the film, converted into metallic zinc, attached to the negative electrode side of the battery. The process of the electrolytic solution for the chemical energy into electrical energy.
In order to confirm the feasibility of the new concept of the battery, experiments in the lab created a small cell sample. They mix the electrolyte separated black zinc iodine solution and colorless zinc iodine solution, were installed in two small bottle analog battery pack liquid storage container. Connected by piping between the pump and a small bottle. They will sample the 12 watt-hour battery capacity into a series of tests to determine the effects of zinc ion and iodine ion battery capacity. The test results indicated that the sample piece of the battery energy storage than is now commonly used in zinc-bromine battery, vanadium batteries, battery fluid is much higher. Compared to lithium-ion battery sulfide, its capacity is still 70% higher.
In addition, zinc iodine batteries safer than conventional batteries,
And can adapt to extreme weather. Of course, it also has shortcomings, it is constantly growing up in the cathode metal zinc precipitation, until finally there may be larger and diaphragm touch. The team hopes the problem of zinc deposited by the addition of alcohol in the electrolyte method will be resolved.